JP6131430B2 - Inspection method for hollow fiber membrane module - Google Patents

Description

  The present invention relates to a method for producing a hollow fiber membrane support in which white turbidity due to elution of an oil agent into a test solution is suppressed.

  In recent years, due to increasing interest in environmental pollution and stricter regulations, water treatment by a membrane method using a filtration membrane excellent in separation completeness and compactness has attracted attention.

  Conventionally, a hollow fiber membrane having a porous membrane layer made of a resin such as polysulfone, polyacrylonitrile, cellulose acetate, or polyvinylidene fluoride is known as a filtration membrane having excellent water permeability. These hollow fiber membranes are produced by microphase-separating a polymer solution and then coagulating the polymer solution in a non-solvent, and have a high porosity and an asymmetric structure. However, such a membrane having only a polymer phase separation structure has a problem that its mechanical strength is not sufficient.

  In order to increase the mechanical strength against this problem, a hollow fiber membrane using a hollow string-like object such as a braid or knitted string as a support has been proposed. (Patent Documents 1 and 2) In particular, a support made of a hollow knitted string is low in cost and excellent in the peel resistance of a polymer porous body.

A general method for producing a hollow fiber membrane using the above string-like material as a support includes the following steps.
(1) Processing into a hollow string-like material (2) Application of a film-forming stock solution to the surface of the string-like material (3) Coagulation, washing and drying of the film-forming stock solution

  The hollow fiber membrane thus formed is a membrane using a surfactant or the like in a state in which the hollow fiber membrane yarn is processed as a single hollow cartridge or a cartridge having both ends fixed (also referred to as a hollow fiber membrane module). Processing such as hydrophilization of the surface and leak inspection are performed (see Patent Document 3).

  By the way, in the manufacture of multifilaments used in the manufacture of such string-like products, in order to prevent yarn breakage and strength reduction during spinning and winding, in addition to spinning oil before spinning and drawing / processing, Usually, after-oil is attached (for example, Patent Documents 4 and 5).

  However, for example, when the hollow fiber membrane obtained by using the string-like material as a support is examined by the method described in Patent Document 3, the spinning oil may remain on the multifilament surface after spinning. Since there are many, the spinning oil and after oil used at the time of manufacture of the support are mixed with the test liquid to form an emulsion in the test liquid, which makes it difficult to confirm because the test liquid becomes cloudy. .

US Pat. No. 5,472,607 International Publication No. 2009/142279 Pamphlet JP 2006-136768 A JP 55-90610 A JP-A-10-219524

  Therefore, in order to solve such a problem, a hollow fiber membrane support that suppresses white turbidity due to elution of an oil agent into a test solution or the like composed of a surfactant or an aqueous solution thereof, and a hollow fiber membrane and a hollow fiber membrane using the support It is an object of the present invention to provide a module.

That is, the present invention is a method for producing a support for a hollow fiber membrane, comprising a step of further processing after oil to a multifilament to which a spinning oil is adhered, and then processing into a hollow string-like product, The present invention relates to a method for producing a support for a hollow fiber membrane, wherein the adhesion amount is 95 % by mass or more and 150% by mass or less with respect to the adhesion amount of the spinning oil.

  The hollow fiber membrane comprising the hollow fiber membrane support and the hollow fiber membrane support obtained by the production method of the present invention and its elements can suppress white turbidity due to elution of an oil agent or the like into the test solution.

It is the schematic which shows an example of the support body for hollow fiber membranes of this invention. It is a schematic block diagram which shows an example of the manufacturing apparatus of the support body for hollow fiber membranes which can be used by this invention. It is a schematic block diagram which shows an example of the hollow fiber membrane manufacturing apparatus which can be used by this invention. It is the schematic which shows an example of the cross-sectional shape of the hollow fiber membrane obtained by this invention.

  Hereinafter, the production method of the hollow fiber membrane support of the present invention will be described in detail. In addition, the following is an example and this invention is not necessarily limited to this description.

(Support structure)
The support for hollow fiber membrane of the present invention is a string-like body in which a multifilament is hollow, and a porous layer is formed by applying a film-forming stock solution on the outer surface of the hollow string and solidifying it. Thus, a hollow fiber membrane is produced.

  FIG. 1 shows a schematic view of a knitted string which is an example of a support for a hollow fiber membrane obtained by the present invention. As described above, the hollow fiber knitted string 10 has a structure in which one multifilament 12 is circularly knitted and the vicinity of the center in the longitudinal direction is hollow.

In the present invention, the fibers constituting the multifilament include synthetic fibers, semi-synthetic fibers, regenerated fibers, natural fibers, and the like.
Synthetic fibers include polyamide fibers such as nylon 6, nylon 66 and aromatic polyamide; polyester fibers such as polyethylene terephthalate, polybutylene terephthalate, polylactic acid and polyglycolic acid; acrylic fibers such as polyacrylonitrile; polyethylene and polypropylene Polyolefin fiber such as polyvinyl alcohol fiber; polyvinylidene chloride fiber; polyvinyl chloride fiber: polyurethane fiber; phenol resin fiber; fluorine fiber such as polyvinylidene fluoride and polytetrafluoroethylene; polyalkylene paraoxybenzoate System fibers and the like.
Examples of the semi-synthetic fibers include cellulose derivative fibers made from cellulose diacetate, cellulose triacetate, chitin, chitosan and the like: protein fibers called promix.
Examples of the regenerated fiber include cellulosic regenerated fibers (rayon, cupra, polynosic, etc.) obtained by a viscose method, a copper-ammonia method, an organic solvent method, or the like. Examples of natural fibers include flax and jute.

  Among these fibers, polyester fiber, acrylic fiber, polyvinyl alcohol fiber, polyamide fiber, or polyolefin fiber, and polyvinyl chloride fiber are particularly preferable because of their excellent chemical resistance, polyester fiber, Acrylic fibers or polyvinyl chloride fibers are particularly preferred.

  In the present invention, the multifilament may be a mixture of two or more different types of fibers. Different types mean that at least one of fineness, single fiber diameter, mechanical properties and materials is different.

(Manufacturing method of support)
FIG. 2 is a schematic configuration diagram illustrating an example of a support manufacturing apparatus. The support body manufacturing apparatus 20 supplies a bobbin 22, a circular knitting machine 24 that circularly knits the yarn 16 drawn from the bobbin 22, and a string supply that pulls the hollow knitted string 12 knitted by the circular knitting machine 24 with a constant tension. A device 26; a heating die 28 for heat-treating the hollow knitted string 12; a take-up device 30 for taking up the heat-treated hollow knitted string 12; and a winder that winds the hollow knitted string 12 around the bobbin as the support 10 32. As shown in FIG. 3, a constant load (tension) may be applied using a dancer roll 27 instead of the string supply device that pulls the hollow knitted string 12 with a constant tension.

  In the support of the present invention, the spinning oil and the after oil are adhered to the multifilament within a range of a certain adhesion amount ratio. Thereby, when manufacturing a hollow fiber membrane using this support body, the cloudiness of a test liquid, a hydrophilizing agent, etc. by mixing both oil agents and emulsifying after manufacture can be suppressed.

  In the present invention, the after-oil adhesion amount is preferably 75 mass% or more and 125 mass% or less with respect to the spinning oil adhesion amount. When the ratio of the amount of the spinning oil and the after oil adhered to the membrane in the above process is less than 75% by mass, fluff is likely to occur in the stringing process, which causes a leak when used as a support for a hollow fiber membrane. There is a fear. On the other hand, when the ratio of the amount of the spinning oil and after oil is greater than 125% by mass, the cloudiness of the test liquid containing the surfactant aqueous solution is significant. More preferably, it is 95 mass% or more and 120 mass% or less.

  The spinning oil is an oil that is usually used in the fiber production process for the purpose of imparting smoothness, antistatic property and the like to the fiber and smoothly spinning, stretching, and post-processing. For example, when the multifilament is a polyester fiber, an oil agent in which a polyethylene oxide or polypropylene oxide ester-based lubricant is a main agent and an ionic surfactant or the like is mixed is generally used. In the present invention, multifilaments using any spinning oil generally used can be used. Such a spinning oil has a relatively high hydrophilicity, and is alone dispersed in a test solution and does not become cloudy.

  As an analysis method of the amount of the spinning oil in the present invention, the oil agent is extracted with a solvent, and any known method such as a method of quantifying the amount of the oil agent in the extract by an analysis method such as infrared spectroscopy and converting it to the amount of adhesion Can be used, but the yarn is washed with a volatile solvent such as methanol, and the amount of oil is obtained from the weight reduction of the yarn after washing.

  After-oil is an oil agent that is applied to prevent yarn breakage and fluff generation before winding of drawn / processed yarn. For example, in the case of a polyester yarn, a mixture of an ester lubricant, mineral oil, a nonionic surfactant such as polyoxyethylene alkyl ether, an ionic surfactant, water or the like is used. In the present invention, any commonly used after oil can be used. Among these components, nonionic surfactants such as ester lubricants, mineral oils, polyoxyethylene alkyl ethers and the like are relatively hydrophobic, which causes the test solution to become cloudy. In particular, after oil is a spinning oil. When the mixture is mixed and an emulsion is formed in the test solution, significant cloudiness is generated. For this reason, it is desirable that the spinning oil and after oil have a combination and quantity ratio that are incompatible when mixed. Whether the spinning oil and the after oil are compatible can be confirmed by mixing the spinning oil and the after oil and visually turbid.

  As a method for analyzing the amount of after-oil deposited in the present invention, the oil agent is extracted with a solvent, and any known method such as a method of quantifying the amount of the oil agent in the extract by an analytical method such as infrared spectroscopy and converting it to the amount deposited However, it is preferable because the method is simple and preferable by washing the support with a volatile solvent such as methanol and reducing the weight of the support after washing to reduce the amount of oil adhering to the yarn.

  When the hollow knitted string 12 passes through the heating die 28, the hollow knitted string 12 is heat-treated at a temperature higher than the thermal deformation temperature of the fiber, and the inner diameter d is equal to or less than the outer diameter D of the hollow knitted string 12 before the heat treatment. By restricting the outer diameter of the hollow braided string 12 on the outlet side of a certain through-hole, the shape of the fiber end protruding on the surface is fixed in a state of being pressed against the surface of the support 10. Moreover, since the hollow knitted string 12 is heat-processed below the fiber melting temperature, the stitches are not crushed. As a result, the film-forming stock solution can sufficiently enter the stitches, and the adhesion between the porous membrane layer and the support 10 can be maintained.

(Method for producing hollow fiber membrane)
Next, examples of the material for the hollow membrane porous membrane layer 11 include polyvinylidene fluoride, polysulfone, polyacrylonitrile, polyethylene glycol, and the like. Polyvinylidene fluoride is preferable because it has both chemical resistance and heat resistance.

When the porous membrane layer 11 is a two-layer composite porous membrane layer, the hollow fiber membrane 1 can be produced, for example, by a production method having the following steps (1) to (6).
(1) The process of apply | coating film forming undiluted | stock solution to the outer peripheral surface of the support body 10,
(2) a step of coagulating the membrane-forming stock solution applied to the support 10 to form a first porous membrane layer to obtain a hollow fiber membrane precursor;
(3) The process of apply | coating a film-forming stock solution to the outer peripheral surface of a hollow fiber membrane precursor,
(4) Step of obtaining a hollow fiber membrane 1 by coagulating the membrane forming stock solution applied to the hollow fiber membrane precursor to form a second porous membrane layer (5) Washing and drying the hollow fiber membrane 1 Process,
(6) A step of winding the hollow fiber membrane 1.
In the above method, the porous membrane layer 11 is composed of two layers, but in the present invention, it may be a single layer or a composite porous membrane layer of three or more layers. Further, when two or more porous membrane layers are formed, using a multiple annular nozzle is preferable because a plurality of layers can be formed in one step.

(Membrane module)
The hollow fiber membrane is usually used after being processed into a hollow fiber membrane module. The membrane module has a main body, an inlet and an outlet for an object to be processed (liquid or gas), and a hollow fiber membrane. Specifically, an inlet and an outlet are provided in the membrane module main body, and a hollow fiber membrane is provided inside the main body. The inlet and the outlet may be provided at both ends of the main body (linear both-end opening type), and either one of the inlet and the outlet may be greatly opened (linear one-side opening type). The hollow fiber membrane is connected to the inside of the main body so as to divide the main body into a first chamber having an inlet and a second chamber having an outlet. The connection includes one in which the end of the hollow fiber membrane is bonded or sealed to the inner wall of the main body, or the end of the hollow fiber membrane is detachably connected to the inner wall of the main body. Therefore, the membrane module of the present invention has a structure in which the liquid and gas introduced from the inlet enter the main body, always pass through the hollow fiber membrane, and are discharged from the outlet.
The inlet, outlet, and main body of the membrane module of the present invention may be made of a metal such as stainless steel or steel, a resin such as a fluororesin, an ABS resin, a polyolefin resin, or a vinyl chloride resin.

  The hollow fiber membrane module of the present invention is a hollow fiber membrane bundle obtained by aligning the hollow fiber membrane bundle obtained by the above-mentioned method in one direction, or the aligned hollow fiber membrane is used as a weft and is made of polyester or polypropylene. After forming a woven or knitted fabric using warp, at least one hollow fiber membrane longitudinal end of the membrane bundle or woven or knitted fabric, the above-described inlet using a known potting resin made of urethane resin or epoxy resin, It can be obtained by connecting to the outlet and the body.

(Inspection method for hollow fiber membrane module)
Usually, the membrane module has a main body, an inlet, an outlet and a hollow fiber membrane as described above, and the hollow fiber membrane divides the main body into a first chamber having an inlet and a second chamber having an outlet. Connected to the inside of the main body. However, each member such as the main body, inlet, outlet, and hollow fiber membrane itself, and defects in the connecting portion between the hollow fiber membrane and the inside of the main body (for example, holes, cracks, incomplete connection, clogging of the hollow fiber membrane, etc.) If it exists, it will not function as a good membrane module. It is therefore necessary to inspect these defects.
Specifically, the inspection method of the membrane module
(1) a step of immersing the hollow fiber membrane module in a test solution;
(2) introducing a test gas from the inlet and discharging it from the outlet through the hydrophobic hollow fiber membrane; and (3) observing bubbles discharged from the hollow fiber membrane module;
Consists of
At this time, if the hollow fiber membrane is damaged or has a large hole, air begins to permeate at a pressure much lower than the expected value, and it can be detected that the membrane is defective. It is difficult to confirm the permeation of the air by visual observation or the like as the generation of bubbles because the test solution becomes cloudy due to the elution mixing of the oil agent.

Hereinafter, the present invention will be described in more detail based on examples.
(Evaluation of the amount of spinning oil and after oil on the hollow fiber membrane support)
Washing the yarn before adhering after-oil with methanol and reducing the weight of the yarn after washing to the ratio of the amount of spun oil attached to the yarn (A). Similarly, reducing the weight of yarn after washing and washing after adhering with methanol and yarn The total oil agent adhesion amount ratio (B) to the yarn was determined, and the after oil adhesion amount ratio to the yarn was calculated from (B)-(A).

(Evaluation of test liquid turbidity of hollow fiber membrane support)
Olphine EXP. A 0.36% aqueous solution of 4036 or a 0.2% aqueous solution of Pluronic RPE 1740 manufactured by BASD was prepared as a test solution. The hollow knitted string was immersed in this test solution in 5% by mass with respect to the test solution and allowed to stand for 3 hours, and then the hollow knitted string was taken out, and the remaining solution was absorbed at 700 nm with a spectrophotometer U-3400 manufactured by Hitachi High-Technologies Corporation. C) was measured. Similarly, the absorbance (D) of the test solution in which the hollow knitted string was not immersed was measured, and the value of (C)-(D) was used as an index of white turbidity.

(Evaluation of the number of fluff generation)
Immediately after the start of string making and at the end, 2 m was cut out with scissors, and the number of fluffs was confirmed visually.

<Example 1>
The support body 10 which consists of the hollow knitted string 12 was manufactured using the support body manufacturing apparatus 20 shown in FIG.
As the multifilament, a polyester fiber having a spin oil adhesion amount of 0.4% (fineness: 84 dtex, number of filaments: 36) was used. Five sets of bobbins 22 each having 5 kg of the polyester fiber wound thereon were prepared.
As the circular knitting machine 24, a table-type string knitting machine (manufactured by Sakurai Textile Machinery Co., Ltd., number of knitting needles: 12, needle size: 16 gauge, spindle circumferential diameter: 8 mm) was used. As the string supply device 26 and the take-up device 30, a Nelson roll was used. As the heating die 28, a stainless steel die having a heating means (inner diameter D: 5 mm, inner diameter d: 2.2 mm, length: 300 mm) was used.

As the after oil, an oil agent (hereinafter referred to as “oil agent A”) composed of mineral oil, sorbitan monooleate, sodium phosphate ester, and polyoxyethylene alkyl ether is used, so that the amount of adhesion is 0.4% by mass with respect to the yarn. After attaching the oil agent to the spinning oil agent (the ratio of after-oil adhesion amount to 100% by mass), the polyester fibers drawn from the bobbin 22 are combined into a yarn 16 (total fineness is 420 dtex), and then the circular knitting machine 24 The hollow knitted string 12 is knitted circularly by knitting, the hollow knitted string 12 is passed through a heating die 28 at 195 ° C., and the heat-treated hollow knitted string 12 is used as the support 10 at a winding speed of 100 m / hr. It wound up on the winding device 32. Production of the support 10 was continued until the polyester fibers on the bobbin 22 were exhausted.
The obtained support 10 had an outer diameter of about 2.5 mm and an inner diameter of about 1.3 mm. The number of the loops 17 of the hollow knitted string 12 constituting the support 10 was twelve per round, and the maximum opening width of the stitches 18 was about 0.05 mm. The length of the support 10 was 12000 m. No thread breakage occurred in the string. In addition, the number of fluff generations was zero. Further, as shown in Table 1, the white turbidity was almost transparent at 0.006.

<Example 2>
A hollow knitted string support was produced in the same manner as in Example 1 except that “NAE2061” manufactured by Matsumoto Yushi Co., Ltd. was used as the after oil. No thread breakage occurred in the string, and the number of fluffs was 0. Further, the white turbidity was almost transparent as 0.020 as shown in Table 1.

<Examples 3 and 4>
The turbidity was evaluated in the same manner as in Example 1 or 2 except that a 0.2% aqueous solution of “Pluronic RPE 1740” manufactured by BASF was used as the test solution. As shown in Table 1, the white turbidity was almost transparent at 0.002 in all Examples.

<Comparative Example 1>
A hollow braided string support was produced in the same manner as in Example 1 except that no after oil was used. Although no yarn breakage occurred in the string, the occurrence of fluff was observed. Further, as shown in Table 1, the white turbidity was almost transparent at 0.003.

<Comparative example 2>
As the after oil, the same procedure as in Example 1 was performed except that the oil agent was adhered so that the adhesion amount of the oil agent A was 0.2% by mass with respect to the yarn (the ratio of the adhesion amount of the after oil to the spinning oil was 50% by mass). A hollow braid was created. As shown in Table 1, the white turbidity was almost transparent at 0.005, but fluff was observed.

<Comparative Examples 3 and 4>
A hollow knitted string was prepared in the same manner as in Example 1 except that the oil agent was adhered so that the amount of adhesion was 2% by mass with respect to the yarn (the amount of adhesion of the after oil to the spinning oil was 500% by mass).
No yarn breakage occurred in the string, and the number of fluffs was 0. However, the white turbidity was 0.420 as shown in Table 1, and the degree of white turbidity was remarkable with respect to the amount of after oil attached. It was.

<Comparative example 4>
A hollow knitted string was prepared in the same manner as in Example 3 except that the oil agent was adhered so that the amount of adhesion was 2% by mass with respect to the yarn (the amount of after oil adhered to the spinning oil was 500% by mass). As shown in Table 1, the cloudiness was 0.402, and the cloudiness was remarkable.

<Example 5>
(Manufacture of hollow fiber membranes)
Using the hollow fiber membrane support shown in Example 1, the hollow fiber membrane 1 was produced by the hollow fiber membrane production apparatus 40 shown in FIG.
As the first spinning dope, 19% by mass of polyvinylidene fluoride (manufactured by Arkema Japan, trade name “Kyner 301F”) and 10% by weight of polyvinylpyrrolidone (trade name “K-79”, manufactured by Nippon Shokubai Co., Ltd.) It was prepared by stirring and dissolving in 71% by mass of dimethylacetamide.
Further, as the second spinning dope, polyvinylidene fluoride (made by Arkema Japan, trade name “Kyner 301F”) 22% by mass and polyvinyl pyrrolidone (made by Nippon Shokubai Co., Ltd., trade name “K-79”) 9% by mass, N, N -Prepared by stirring and dissolving in 69% by mass of dimethylacetamide. Next, the second film-forming stock solution is supplied to the outer line of the triple annular nozzle kept at 30 ° C. having a diameter of 5.24 mmφ, and the first film-forming stock solution is supplied to the inner line, and the support 10 is placed at the center of the nozzle. After passing two layers of the film-forming stock solution on the support and laminating it, it was passed through a 40 mm air gap to 75 ° C. consisting of 8% by mass of N, N-dimethylacetamide and 92% by mass of water. It was allowed to coagulate by passing through a heat-retaining coagulation bath.
The obtained hollow fiber membrane was washed in hot water at 98 ° C. to remove a part of the remaining N, N-dimethylacetamide and polyvinylpyrrolidone, and then the following steps (a) to (d) were carried out in 3 steps. Repeatedly, after removing the remaining polyvinylpyrrolidone, it was dried at 90 ° C.
(A) a step of immersing the hollow fiber membrane in a 10% by mass sodium hypochlorite aqueous solution,
(A) a step of heating the hollow fiber membrane in a steam bath at 90 ° C.
(C) washing the hollow fiber membrane in hot water at 90 ° C.,
(D) A step of immersing and washing the hollow fiber membrane in water at room temperature.

(Manufacture of hollow fiber membrane modules)
First, five knitted fabrics having a width of 1000 mm and a knitting length of 2000 mm were knitted using polyester as warp yarns and three hollow fiber membranes aligned to obtain a hollow fiber membrane knitted fabric laminate. Next, the previously prepared hollow fiber membrane laminate was inserted into the opening of the water collection tube until it hits the split core, and polyurethane resin was injected from the opening to the vicinity of the root of the hollow fiber membrane knitted fabric laminate and solidified. .
As described above, a hollow fiber membrane module having a hollow fiber membrane opening in the water collection tube was obtained. The effective membrane area of this hollow fiber membrane module was 25 m ² .

As shown in Table 1, the white turbidity of the test solution after the test of the membrane module was almost transparent as 0.001.

<Example 6>
A hollow fiber membrane module was prepared in the same manner as in Example 5 except that the hollow fiber membrane support shown in Example 2 was used. As shown in Table 2, the turbidity of the test solution after the test was almost transparent at 0.004.

<Comparative Example 5>
A hollow fiber membrane module was prepared in the same manner as in Example 5 except that the hollow fiber membrane support shown in Comparative Example 2 was used. As shown in Table 2, the cloudiness of the test solution after the test was 1.400, and the cloudiness was remarkable.

1 Hollow fiber membrane 10, 12 Hollow support (string)
DESCRIPTION OF SYMBOLS 11 Porous membrane layer 16 Multifilament 22 Bobbin 24 Knitting machine 26 String supply apparatus 28 Die 30 Take-out apparatus 42 Nozzle (multiple annular nozzle)
44 Stock solution supply device 46 Coagulation bath 48 Guide roll

Claims (4)

A method for producing a support for a hollow fiber membrane, comprising the step of further attaching after oil to a multifilament to which a spinning oil is adhered, and then processing into a hollow string-like body, wherein the amount of the after oil adhering to the multifilament A plurality of hollow fiber membranes including a hollow fiber membrane support obtained by the method for producing a support for hollow fiber membranes that is 95% by mass or more and 150% by mass or less with respect to the amount of adhesion of the fiber are obtained. A method for inspecting a hollow fiber membrane module in which at least one end portion is connected to a module body, comprising the following steps (1) to (3).
(1) A step of immersing the hollow fiber membrane module in a test solution;
(2) a step of introducing an inspection gas from the inlet of the hollow fiber membrane module and discharging the gas from the outlet of the hollow fiber membrane module through the hollow fiber membrane;
(3) observing bubbles discharged from the hollow fiber membrane module; The method for inspecting a hollow fiber membrane module according to claim 1, wherein the step of processing the hollow string-like body is a circular knitting using a knitting machine . Hollow fiber membrane, the method for producing a hollow fiber membrane comprising the steps of forming a porous membrane layer made of a thermoplastic resin on the surface of the manufactured hollow fiber membranes for support by the production method according to claim 1 or 2 The method for inspecting a hollow fiber membrane module according to claim 1, wherein the hollow fiber membrane is obtained. The step of forming a porous membrane layer made of a thermoplastic resin comprises passing a hollow fiber membrane support from the center using a multi-annular nozzle and applying the porous membrane layer to the side thereof. Inspection method of hollow fiber membrane module of description .

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